/Engine/Plugins/2D/Paper2D/Source/Paper2D/Classes/PaperFlipbookActor.h
This actor is created when you drag a flipbook asset from the content browser into the level, and it is just a thin wrapper around a UPaperFlipbookComponent that actually references the asset.
[UCLASS](Programming/UnrealArchitecture/Reference/Classes#classdeclaration)(ComponentWrapperClass) class PAPER2APaperFlipbookActor : public [AActor](API\Runtime\Engine\GameFramework\AActor)